1. Field
Example embodiments relate to semiconductor dies, light-emitting devices (LEDs), methods of manufacturing and methods of generating multi-wavelength light.
2. Description of the Related Art
Light emitting devices (LEDs) are relatively efficient and environmentally friendly light sources. LEDs are used in a variety of fields such as displays, optical communications, automobiles, and general lighting.
A conventional LED uses a fluorescent material to generate white light. In one example, white light is obtained by exciting red, green, and blue fluorescent materials with an ultra violet (UV) ray to emit red, green, and blue light to obtain white light. Yellow light is emitted by exciting a yellow fluorescent material that is complementary to a blue LED used as a light source to obtain white light.
Conventionally, a white color light may be generated using LEDs without a fluorescent material. In one example, each of a plurality of LEDs emits one of red, green, and blue visible rays, which are used in combination to generate the white color light. For example, an LED having an indium-gallium-nitride (InGaN) layer as a light emitting material uses the fact that the emitted color varies according to a change in mole fraction of indium (In) in the InGaN layer. However, as the content of indium (In) increases, the lattice constant increases, which results in a relatively large lattice mismatch between the relatively thin InGaN layer and a base substrate. Thus, light emission efficiency may deteriorate from a relatively short wavelength to a relatively long wavelength.